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  1. #include <iostream>
  2. #include <list>
  3. #include <string>
  4. #include <memory>
  5. using namespace std;
  6.  
  7. class Animal {
  8. public:
  9.     virtual void speak() = 0;
  10.     virtual ~Animal() {}; // Always a good thing if the class has virtual members
  11.     string name;
  12. };
  13.  
  14. class Dog : public Animal {
  15. public:
  16.     Dog(string n) { this->name = n; }
  17.     void speak() { cout << this->name << " says WOOF!" << endl; }    
  18. };
  19.  
  20. class AnimalQueue {
  21.     std::list<Animal*> animals;
  22. public:
  23.     void enqueue(Animal* a) {
  24.         animals.push_back(a); // Copy the pointer
  25.     }
  26.     Animal* dequeue() {
  27.         Animal *d = animals.front();
  28.         animals.pop_front(); // Destroy the pointer
  29.         return d;
  30.     }
  31. };
  32.  
  33. int main() {
  34.     AnimalQueue q;
  35.     std::unique_ptr<Dog> d = std::make_unique<Dog>("Rex");
  36.     q.enqueue(d.get()); // This will now store the pointer to the object
  37.  
  38.     // Try with dog-specific command
  39.     Animal *sameDog = q.dequeue(); // d.get() and sameDog are now pointing at the same object
  40.     if (d.get() == sameDog)
  41.     	std::cout << "d.get() == sameDog" << std::endl;
  42.     std::cout << sameDog->name << std::endl;// Prints "Rex"
  43.     sameDog->speak();
  44.  
  45.     return 0;
  46. }
Success #stdin #stdout 0s 3276KB
comments ()
stdin 
Standard input is empty
stdout 
d.get() == sameDog
Rex
Rex says WOOF!
https://ideone.com/UcUlNY
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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